Hot liquid metal pumps



H. W. LAM B HOT LIQUID METAL PUMPS Oct. 16, 1962 3,058,432

Filed Oct. 31. 1960 2 Sheets-Sheet 1 Harold WLamb INVENTOR.

. BY 7 0/ W 6 14 g g A1 TOR/YE/ 1962 H; w. LAMB 3,058,432

HOT LIQUID METAL PUMPS Filed Oct. 51, 1960 2 Sheets-Sheet 2 I'E I ll 64 Harold WT Lamb INVENTOR.

BY )V "Wt/Z14 A Tram/5y States This invention relates to pumps of the general type which includes at least a pair of cylinders into which liquid is admitted at the bottom by gravity and is then forced therefrom by air or other gas pressure admitted into the cylinders above the highest liquid level in automatically controlled alternating sequence.

The broad object of the present invention is to provide a pump of the type mentioned which is especially adapted for pumping molten zinc or other hot liquid metal. In the construction of such a pump I have found refractory ceramic material to be the most practical for withstanding the extreme heat and other conditions involved in the pumping of molten metal.

Therefore one of the more specific objects of the present invention is to provide a liquid metal pump of the type mentioned of strong, efiicient and durable design in which the base which houses the liquid metal inlet and outlet chambers containing the necessary control valves, the cylinders and the liquid metal discharge pipe are all formed in separate parts pressed or molded from refractory ceramic material held in rigidly assembled relation by means of tie rods shielded from the liquid metal by ceramic or other heat resistant insulation, the joints between adjacent parts also being sealed by heat resistant cement. The movable valve members in the inlet and outlet chambers also are made of refractory ceramic material, so that the entire pump with the exception of the tie rods and associated nuts, is made of such material.

Another object of this invention is to provide a pump of the character mentioned in which the level of the liquid metal in the cylinders is limited to a plane a substantial distance below the upper ends of the cylinders. This not only protects the air pressure inlet and exhaust valves and pipes from effects of the hot metal, but also eliminates the necessity of providing float valves in the cylinders to preclude the escape of liquid metal into the air inlet ports in the upper ends of the cylinders, thus leaving the cylinders entirely free from any moving parts.

A further object of the invention is to provide the upper ends of the tie rods clamping the cylinders to the base with spring means for permitting longitudinal expansion and contraction of the rods, and still maintain their clamping effect. Since the tensile strength of ceramic material is relatively low, the tie rods with the force of the springs also reinforce the walls of the cylinders and overcome the stresses tending to cause cracks in the walls of the cylinders.

A still further object of this invention is to provide efiicient means for insulating the ends of all tie rods which are subjected to contact with the liquid metal.

In my improved pump construction the liquid metal discharge pipe is of substantially lesser diameter than the cylinders and with its outlet preferably a short distance above the highest liquid metal level in the cylinders, thereby leaving it far removed from the valves in the upper ends of the cylinders, and also facilitating the discharge of the liquid metal from the pump.

In addition to being resistant to the extreme heat of the liquid metal the ceramic parts of my improved pump have another important advantage in that the surfaces are uniformly smooth thereby leaving no rough places in which an accumulation of metal can begin.

Other objects and advantages of my improved pump will be apparent or pointed out in the following speciatent ficati-on in which reference is had to the accompanying drawings forming a part thereof, and in which FIG. 1 is a side elevation of one form of pump in accordance with the present invention;

FIG. 2 is a rear elevation of the pump shown in FIG. 1;

FIG. 3 is a top plan view of the pump;

FIG. 4 is a detail view showing the spring means for permitting expansion and contraction of the cylinder tie rods;

FIG. 5 is a schematic sectional view of a three-way valve for controlling the flow of air pressure into and from the cylinders of the pump;

FIG. 6 is a detail sectional view showing the manner of sealing the ends of the tie rods exposed to hot liquid metal;

FIG. 7 is a section taken on the line 7-7 of FIG. 2;

FIG. 8 is a section also taken on the line 7-7, but looking upwardly, instead of downwardly as in FIG. 7;

FIG. 9 is a section taken on the line 9-9 of FIG. 3;

FIG. 10 is a section taken on the line 1010 of FIG. 2; and

FIG. 11 is a section taken on the line 11ll1 of FIG. 3.

Referring to the drawings, in which like reference numerals designate like parts in the several views, the base designated generally by the numeral 10 is formed entirely of ceramic plates including a rectangular top plate 12, a similar bottom plate 14, side plates 16, end plates 18 between and in perpendicular relation with the plates 16, a central partition plate 20 between and in perpendicular relation with the end plates 18, a pair of transverse plates 22 between and in perpendicular relation with partition plate 20 and one of the side plates 16, and a pair of spaced valve seat plates 24 between and in pe-r pendicular relation with partition plate 26, the intermediate plates being held in rigidly assembled relation by means of tie rods 26 projecting transversely through the end portions of side plates 16 and longitudinally through end plates 18, these tie rods terminating short of the outer surfaces of side plates 16 in recesses 30.

Nuts 32 on the tie rods 26 inside the recesses 30 clamp the end plates 18 between the side plates 16, the nuts 32 and the ends of the rods being incased in ceramic insulating material 34 inserted into the recesses 30 in a plastic state and hardened. The top and bottom plates 12 and 14 are held in clamped relation with the edges of partition plate 20, the transverse plates 22 and the valve seats 24 by means of longer tie rods 36 which project through flanges 38 on the upper ends of cylinders 40 and through top plate 12, partition plate 20, one side plate 16 and bottom plate 14, thereby also clamping the cylinders in recesses 42 in top plate 12. Additionally a pair of short tie rods 44 may be inserted through the top and bottom plates and one side plate to more rigidly clamp these plates to the intermediate plates. The long tie rods 36 are incased from the flanges 38 to the top plate 12 in ceramic insulating casings 46 which are seated at their lower ends in recesses 48 in the top plate 12. Helical springs 50 are mounted around the upper ends of tie rods 36 between nuts 52 and the cylinder flanges 38 for the purpose of permitting longi tudinal expansion and contraction of the rods while maintaining their clamping action, and also reinforcing the walls of the cylinders, as previously mentioned. At their bottom ends these rods are incased in ceramic insulating material 34 the same as described in connection with tie rods 26, and as shown in enlarged detail in FIG. 6.

The assembly of ceramic plates referred to in the foregoing description forms a pair of liquid metal inlet chambers 54 immediately below the ends of the cylinders 40 and in communication with the cylinders through ports 56 in the top plate 12. The bottom plate 14 has liquid metal inlet ports with valve seats 58 and ceramic ball valves 60 controlling the flow through the valve seats. The assembly of parts described also forms a liquid outlet chamber 62 in communication through ports and valve seats 64 in the valve seat plates 24 with separate chambers 66 in communication with the inlet chambers 54 through ports 68 in the partition plate 20, the valve seats 64 being controlled by a ceramic ball valve 70.

A liquid metal discharge pipe 72 is of substantially lesser diameter and shorter than the cylinders 40, and terminating at its upper end in a horizontally directed outlet 74 to which a pipe 76 (FIG. 1) may be connected for delivery of molten metal to any desired location. This pipe is clamped in a recess 78 in the top plate 12 by means of insulated tie rods 80 which project through a yoke 82 extending across the top of the pipe and through top plate 12. The tie rods terminate in recesses in the yoke and top plate and are provided with clamping nuts 32, corresponding to recesses 30, nuts 32 and ceramic insulation 34 shown in FIG. 6 and also incased with ceramic casings 84 corresponding to the casings 46 inclosing tie rods 36. The bottom end of the pipe 72 is in communication with liquid metal outlet chamber 62 through ports 86 in the top plate 12.

The molten or liquid metal 88 may be contained in a tank 90 or other suitable reservoir into which the pump may be partially submer ed, with means (not shown) for limiting its level to a plane below the outlet 74. Although this level will limit the level of liquid metal admitted by gravity into the cylinders 40 it is not essential that the liquid metal level be maintained in a fixed plane, since the level may vary without materially aifecting the operation of the pump. The liquid metal admitted by gravity into the cylinders 40 through valve seats 58 in the bottom plate 14 is forced from the cylinders 40 into the discharge pipe 72 in alternately sequential cycles by means of air or other gas pressure admitted into the upper ends of the through conventional electrical 3-way valves 92 connected with an air pressure supply pipe 94, the valves being provided with air pressure exhaust outlets 96 (as shown schematically in FIG. the sequential operation of the valves 92 being controlled by any suitable conventional automatic means (not shown).

As previously mentioned all the joints between the various ceramic parts are sealed with heat resistant cement 98, as indicated in FIG. 6, so that the whole pump structure is capable of prolonged operation without danger of deterioration from contact with .hot. liquid metal, and yet with all the efliciency obtained in metal pumps in the pumping of cooler liquids.

It should be understood that, as shown in FIGS. 9 and 11, the exhaust outlet 96 of the valve 92 at the right in FIG. 11 is open and that the air pressure in the associated cylinder 40 has been exhausted to the atmosphere thus permitting the cylinder to fill with liquid metal from the tank 9tlthrough the valve seat 58 in bottom plate 14; also that the exhaust outlet 96 in the valve 92 of the other cylinder 40 is closed and that air pressure is forcing the liquid metal in its associated cylinder out through the outlet 74 o-f the discharge pipe 72. As already mentioned any suitable electrical means for automatic sequential control of the valve operation may be employed, and forms no part of the present 1nvention.

As illustrated and described the inlet and outlet chambers S4 and 62 and the chambers 66 are all formed by the plates 12, 14, 16, 18, 20, 22 and 24 constituting a rigid framework containing the necessary chambers and valve seats clamped between the top and bottom plates 12 and 14, thus forming a complete rigid unit. It should be noted that while the manner of construction illustrated and described has been found to be the most practical in the use of ceramic material, it would be possible to mold or press the entire framework disposed between plates 12 and 14 in one piece. It would also be possible to mold or press the framework referred to integrally with the top or bottom plates. These possible modifications being obvious are not separately illustrated in the drawings.

From the foregoing description it will be apparent that I have provided a pump for the purpose described of simple, efiicient and durable construction in which all the major working parts are made from refractory ceramic material and in which the working parts are protected from any detrimental elfects of hot molten metal flowing through the various parts of the pump. It will also be apparent that while the embodiment of the pump illustrated has only two cylinders it is possible with modified arrangements of the cylinders and liquid metal outlet to increase the number of the cylinders employed in the pump, as desired.

Obviously, various changes and modifications may be made in my improved pump without departing from the spirit and scope of my invention. Therefore, it should be understood that the embodiment of the invention shown and described is intended to be illustrative only, and restricted only by the appended claims.

Iclaim:

1. A liquid metal pump of the character described comprising a housing formed from top and bottom plates having therebetween a separate framework vertically spacing said plates apart and forming side walls for said housing inclosing a space inside the peripheral edges of said plates, said framework having longitudinal and transverse partitions dividing said space into, at least, a pair of liquid metal inlet chambers having inlet ports in said bottom plate, and a liquid metal outlet chamber defined by the housing walls and the partition walls in communi cation with said inlet chambers; at least, a pair of cylinders in perpendicular relation with said top plate and in communication with said inlet chambers, valve means in said inlet chambers for controlling the flow of liquid metal through said inlet ports into said inlet chambers and cylinders and from said cylinders and inlet chambers into said outlet chambers, a liquid metal discharge pipe in perpendicular relation with said top plate and in communication with said outlet chamber, valve means in said liquid metal outlet chamber for controlling the flow of liquid metal from said inlet chambers into said outlet chamber and through said discharge pipe; gas pressure inlet and outlet ports in the upper ends of said cylinders, and valve means for controlling the flow of gas pressure through said ports; said top and bottom plates, the framework therebetween, the cylinders and the discharge pipe being formed in separate parts from refractory ceramic material; means for clamping said parts together in assembled relation with said cylinders and discharge pipe abutting said top plate in the aforesaid relation with said liquid metal inlet and outlet chambers, said means including tie rod supports on said cylinders and discharge pipe and tie rods engaging said supports and said housing, the tie rods for said cylinders and discharge pipe being incased in refractory ceramic material, the tie rods for said cylinders projecting through said housing into engagement with said bottom plate; spring means cooperative with said tie rods and their supports on said cylinders for compressing said cylinders and housing parts together while permitting thermal longitudinal expansion and contraction of said rods; the joints between all adjacent ceramic parts of said pump being cemented with heat resistant cement.

2. A liquid metal pump as in claim 1 in which the tie rod supports on the cylinders comprise flanges on the upper ends of the cylinders, and in which the tie rods project through openings in said flanges and through the bottom plate into recesses formed therein, said rods terminating short of the open ends of said recesses, said rods having thereon clamping nuts in said recesses, said nuts and rod ends being incased in refractory ceramic material; the spring means for compressing the cylinders and housing parts together comprising hciical springs on said rods between the flanges on said cylinders and nuts on the ends of said rods.

3. A liquid metal pump as in claim 1 in which the means for attaching the discharge pipe to the top plate includes a yoke extending across the upper end of the pipe and a pair of diametrically opposed tie rods projecting through the end portions of the yoke through the top plate, the ends of said rods terminating in recesses in the top of the yoke and the bottom of the top plate and having nuts on their end portions incased in the recesses with refractory ceramic material, said rods also being incased from said yoke to the top plate in refractory ceramic material.

4. A liquid metal pump as in claim 1 in which the framework between the top and bottom plates is formed from side and end plates, a longitudinal central partition plate, a transverse plate between said partition and one side plate forming the liquid metal inlet chambers and a pair of longitudinally spaced transverse plates between the partition and the other side plate, said transverse plates forming the liquid metal outlet chamber therebetween and additional chambers at the ends of the partition in communication with the inlet chambers, and ported valve seats in said transverse plates communicating said end chambers with said outlet chamber, said side and end plates being clamped in rigidly assembled relation by means of longitudinally extending tie rods and nuts at their ends, said nuts and rod ends being incased in refractory ceramic material.

5. A liquid metal pump as in claim 1 in which the valve means for controlling the flow of liquid metal through the inlet ports into the inlet chambers include flaring valve seats for said ports and a pair of ceramic balls for closing and opening said ports, and in which the valve means for controlling the flow of liquid metal from the inlet chambers into the outlet chamber include a pair of ported valve seats in facing relation at each end of said outlet chamber and a single ceramic ball therebetween for closing and opening the ports in said valve seats.

References Cited in the file of this patent UNITED STATES PATENTS 2,553,276 Reed May 15, 1951 2,674,640 Tama Apr. 6, 1954 2,723,187 Hubmann Nov. 8, 1955 2,730,961 Yeomans Jan. 17, 1956 2,857,852 Carignani Oct. 28, 1958 2,937,789 Tama May 24, 1960 

